/*
 * @Author: cqg
 * @Date: 2021-05-19 09:44:13
 * @LastEditTime: 2021-05-19 10:06:57
 * @Description: 饿了么弹窗拖拽（参照于民间文档：https://blog.csdn.net/sinat_21902709/article/details/86545444）
 * @LastEditors: cqg
 */
export default {
	install(Vue) {
		Vue.directive("dialogDrag", {
			bind(el, binding, vnode, oldVnode) {
				//弹框可拉伸最小宽高
				let minWidth = 400;
				let minHeight = 300;
				//初始非全屏
				let isFullScreen = false;
				//当前宽高
				let nowWidth = 0;
				let nowHight = 0;
				//当前顶部高度
				let nowMarginTop = 0;
				//获取弹框头部（这部分可双击全屏）
				const dialogHeaderEl = el.querySelector(".el-dialog__header");
				//弹窗
				const dragDom = el.querySelector(".el-dialog");
				//给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；
				dragDom.style.overflow = "auto";
				//清除选择头部文字效果
				//dialogHeaderEl.onselectstart = new Function("return false");
				//头部加上可拖动cursor
				dialogHeaderEl.style.cursor = "move";
				// 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
				const sty =
					dragDom.currentStyle || window.getComputedStyle(dragDom, null);
				let moveDown = e => {
					// 鼠标按下，计算当前元素距离可视区的距离
					const disX = e.clientX - dialogHeaderEl.offsetLeft;
					const disY = e.clientY - dialogHeaderEl.offsetTop;
					// 获取到的值带px 正则匹配替换
					let styL, styT;
					// 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
					if (sty.left.includes("%")) {
						styL =
							+document.body.clientWidth * (+sty.left.replace(/\%/g, "") / 100);
						styT =
							+document.body.clientHeight * (+sty.top.replace(/\%/g, "") / 100);
					} else {
						styL = +sty.left.replace(/\px/g, "");
						styT = +sty.top.replace(/\px/g, "");
					}
					document.onmousemove = function(e) {
						// 通过事件委托，计算移动的距离
						const l = e.clientX - disX;
						const t = e.clientY - disY;
						// 移动当前元素
						dragDom.style.left = `${l + styL}px`;
						dragDom.style.top = `${t + styT}px`;
						//将此时的位置传出去
						//binding.value({x:e.pageX,y:e.pageY})
					};
					document.onmouseup = function(e) {
						document.onmousemove = null;
						document.onmouseup = null;
					};
				};
				dialogHeaderEl.onmousedown = moveDown;
				//双击头部全屏效果
				dialogHeaderEl.ondblclick = e => {
					if (isFullScreen == false) {
						nowHight = dragDom.clientHeight;
						nowWidth = dragDom.clientWidth;
						nowMarginTop = dragDom.style.marginTop;
						dragDom.style.left = 0;
						dragDom.style.top = 0;
						dragDom.style.height = "100VH";
						dragDom.style.width = "100VW";
						dragDom.style.marginTop = 0;
						isFullScreen = true;
						dialogHeaderEl.style.cursor = "initial";
						dialogHeaderEl.onmousedown = null;
					} else {
						dragDom.style.height = "auto";
						dragDom.style.width = nowWidth + "px";
						dragDom.style.marginTop = nowMarginTop;
						isFullScreen = false;
						dialogHeaderEl.style.cursor = "move";
						dialogHeaderEl.onmousedown = moveDown;
					}
				};
				dragDom.onmousemove = function(e) {
					let moveE = e;
					if (
						e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 ||
						dragDom.offsetLeft + 10 > e.clientX
					) {
						dragDom.style.cursor = "w-resize";
					} else if (
						el.scrollTop + e.clientY >
						dragDom.offsetTop + dragDom.clientHeight - 10
					) {
						dragDom.style.cursor = "s-resize";
					} else {
						dragDom.style.cursor = "default";
						dragDom.onmousedown = null;
					}
					dragDom.onmousedown = e => {
						const clientX = e.clientX;
						const clientY = e.clientY;
						let elW = dragDom.clientWidth;
						let elH = dragDom.clientHeight;
						let EloffsetLeft = dragDom.offsetLeft;
						let EloffsetTop = dragDom.offsetTop;
						dragDom.style.userSelect = "none";
						let ELscrollTop = el.scrollTop;
						//判断点击的位置是不是为头部
						if (
							clientX > EloffsetLeft &&
							clientX < EloffsetLeft + elW &&
							clientY > EloffsetTop &&
							clientY < EloffsetTop + 100
						) {
							//如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;
						} else {
							document.onmousemove = function(e) {
								e.preventDefault(); // 移动时禁用默认事件
								//左侧鼠标拖拽位置
								if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
									//往左拖拽
									if (clientX > e.clientX) {
										dragDom.style.width =
											elW + (clientX - e.clientX) * 2 + "px";
									}
									//往右拖拽
									if (clientX < e.clientX) {
										if (dragDom.clientWidth < minWidth) {
										} else {
											dragDom.style.width =
												elW - (e.clientX - clientX) * 2 + "px";
										}
									}
								}
								//右侧鼠标拖拽位置
								if (
									clientX > EloffsetLeft + elW - 10 &&
									clientX < EloffsetLeft + elW
								) {
									//往左拖拽
									if (clientX > e.clientX) {
										if (dragDom.clientWidth < minWidth) {
										} else {
											dragDom.style.width =
												elW - (clientX - e.clientX) * 2 + "px";
										}
									}
									//往右拖拽
									if (clientX < e.clientX) {
										dragDom.style.width =
											elW + (e.clientX - clientX) * 2 + "px";
									}
								}
								//底部鼠标拖拽位置
								if (
									ELscrollTop + clientY > EloffsetTop + elH - 20 &&
									ELscrollTop + clientY < EloffsetTop + elH
								) {
									//往上拖拽
									if (clientY > e.clientY) {
										if (dragDom.clientHeight < minHeight) {
										} else {
											dragDom.style.height =
												elH - (clientY - e.clientY) * 2 + "px";
										}
									}
									//往下拖拽
									if (clientY < e.clientY) {
										dragDom.style.height =
											elH + (e.clientY - clientY) * 2 + "px";
									}
								}
							};
							//拉伸结束
							document.onmouseup = function(e) {
								document.onmousemove = null;
								document.onmouseup = null;
							};
						}
					};
				};
			}
		});
	}
};
